


Burn Them All

by Aria_Lerendeair



Series: Love Letters [2]
Category: Shadowhunters (TV), The Shadowhunter Chronicles - All Media Types, The Shadowhunter Chronicles - Cassandra Clare
Genre: Alec is Captured, BAMF Magnus Bane, Blood Magic, Canon-Typical Violence, Hurt Alec Lightwood, M/M, Magnus is a Magical Badass, Magnus saves the day, Ruthless Magnus Bane
Language: English
Status: Completed
Published: 2019-08-31
Updated: 2019-08-31
Packaged: 2020-10-04 06:17:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,133
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20466392
Author URL: https://archiveofourown.org/users/Aria_Lerendeair/pseuds/Aria_Lerendeair
Summary: When Alec is captured, Magnus will stop at nothing to rescue him, and burn down all in his path keeping them apart.





	Burn Them All

**Author's Note:**

> So this got....slightly delayed...due to a bunch of other fic ideas! 
> 
> But, here's the next portion of Love Letters! 
> 
> These characters don't belong to me, I'm just borrowing them to have some fun!

“-and magic, while it can be fickle at best, is neither good nor evil. It simply is, and however it’s used is determined by the person wielding it, understood?” 

A chorus of younger voices called out, “Yes, Mr. Lightwood-Bane.” 

Magnus grinned at them all and gave a wink. “Now I’ve finished my boring lecture part of today’s class, and if you can all promise to remember what I taught you today…” the response in the room was instant and loud with shouted promises. “We can have some fun.” 

He was halfway through an explanation on transmutation and how it was far more difficult to create something from scratch than it was to change something else when the alarms in the Institute blared, making the children in front of him jump. 

“Don’t worry. It’s just the proximity alarm,” he mentioned to them, but then the alarm rang again, three times in quick succession. There’d been an attack on Shadowhunters. His heart stopped beating for several long seconds. Alexander had been out on patrol. A routine inspection. 

“Mr. Magnus?” A quiet voice asked. 

Magnus turned to one of the children was pointed to his hands. Blue fire and sparks were chasing around his skin, a testament to how barely restrained his magic was. His magic was pounding through him demanding he find Alexander and find him now. 

Clary burst through the door and stared at him. Magnus felt his heart drop. 

“I’ve got the children. Izzy made it back. They took Alec. You need-“ 

Magnus didn’t bother waiting for the rest of the sentence, he portaled into the hallway by the debriefing rooms, moving past them until he saw Isabelle and Raj. Another quick portal and he was in the room. 

“Who?” He demanded, staring them both down. “Where?” 

“Circle members,” Izzy spat. “Had a warlock helping them, Alec shoved me out of the way of his last attack and ordered me here, to tell you.” 

“You mean the Clave?” Raj asked, his fingers pausing in the typing of his report. 

The buzzing under his skin was getting stronger. Alexander had been kidnapped by one of his own kind who was helping the Circle. He could hear the sparks and snaps of the magic around his hands, was well aware that the color had turned a dark, deep red. 

“No. Alec knew who he needed,” Izzy said, staring straight at Magnus. “Jace is in enough pain that he can’t move, Magnus. It’s all coming from Alec.” 

Magnus couldn’t breathe, his blood and magic were pounding in his ears, a demand that he kill any and all in his path, that he burn and destroy them all. “Where?” 

“45th. By the docks. Last place I saw him. He shot an arrow on a nearby roof - I thought he’d missed, but he never misses. Think he was giving you something to track.” 

It shouldn’t surprise him, his planner, being so smart, knowing that he would come after him. “Alert the Clave. Tell them I will handle this issue... _ personally _ .” 

“What-you don’t have the authority to do that!” 

Magnus ignored the protest from Raj and smiled at Isabelle. “Why don’t you ask the acting Head of the Institute sitting across from you if she disagrees with me.” He didn’t bother waiting for an answer. He had his location, and he had a way to track Alec. That was what mattered. 

He opened another portal, well aware that it was far from the normal color of his magic and stalked through it. He couldn’t afford to wait, Alexander could not afford to have him wait. Magic pounded through his veins, feeding off his anger, demanding that he burn, that he wreck havoc and destroy all his in his path to bring his Alexander back. 

It was on the fourth rooftop that Magnus found the arrow Isabelle had told him about. Magnus strode to it, wrapping his fingers down the shaft, closing his eyes as his magic flared around it. Desperation weighed heavily on it. His eyes flashed as he felt Alexander draw the bow and shoot, shoving Isabelle out of the way as he was hit with a blast from the warlock. 

Then pain. Nothing but pain. The arrow snapped, his magic responding to the last emotions he had felt from Alexander. But he knew where they were now. He knew that they were coming for him, not for Alexander, and that his husband was simply a means to an end. Magnus portaled down to where the remains of the fight were, his magic snapping around him, angry and blood red. 

Magnus stood and waited, listening. It was a matter of seconds before he heard it. The sound of claws on concrete, the low, harsh, snarling breath of demons, pouring out of the shadows to surround him. He watched them form a tight circle around him, snarling at each other, eager to step closer. It wasn’t until a Shax demon moved in that Magnus allowed his power to erupt, turning the demon to ash with a flick of his finger. 

It felt  _ good _ . He would kill them all, and he would show them what a mistake it was to try and take what was  _ his _ _._ They had made a mistake coming after him and Magnus would make them pay for it, in blood and pain. 

However, it appeared he was still being toyed with. No one else appeared and the demons were beginning to pace in an impatient circle around him. His eyes flashed and his power erupted out of him in a flare of fire, electricity and shadow. The demons were gone in a matter of seconds and he had not even felt the strain of the magic used. 

This was the legacy of his father. Asmodeus had been a Prince of Hell, and he? Magnus smirked, his eyes flashing again as he let his magic fade back until it danced around his fingertips. He was Asmodeus’ son. 

“Impressive. And here I thought the pet warlock for the shadowhunters wouldn’t put up much of a fight.” 

Magnus turned in the direction of the voice and took in the sight of her. He could smell the stink of blood magic on her. A disciple of Lilith, then. He let his magic flare around his hands, expressing his anger and fury better than he ever could. 

“It would be wise for you to tell me where Alexander is,” Magnus said, taking a step towards her. He could see her gathering her magic around her hands but it was laughable in the face of his fury. “If I find him alive, I will make your death a quick one.” 

Her only response was a cackle and Magnus watched with disinterest as she gathered more power in her palms, the magic moving slow and sickly. She fired a ball of flame at him, but his magic was flame and shadow and it was easy to catch the ball and hold it in his palm. Her eyes widened and Magnus extinguished the flame with a quick clench of his fist. He took a step towards her, his eyes narrowing when her posture tensed in fear. 

“You’re too late!” She shouted, stepping back to gather more magic around her arms. “We needed his pretty angel blood and now-hrrnk!” 

Magnus twitched his finger and tightened the collar of red magic around her throat, lifting her off the ground, watching her struggle against the hold he had her in. “I hope,” he whispered, stepping closer to her. “For your sake? You are wrong. If I find my husband dead,” Magnus tightened the collar again, stepping closer to her, lowering her to the ground so he could meet her eyes. “There is no where you can run to, no where on this earth you can go to hide that I will not find you and make you  _ suffer _ for what you helped to do.” 

Her eyes were wide with fear now and Magnus gave her a bland smile. “Tell me where he is.” 

“Th-the warehouse, end of the docks!” She blurted. 

Magnus hummed, leaning in closer to her. “So disloyal. So ready to save your own skin. Perhaps I should tell them and they will take care of you for me.” He twitched his fingers and had her unconscious in an instant. He left her lying in a pool of ichor and turned to the warehouse. 

Now that he was looking for it, it was easy to see the heavy magic gathering around the warehouse. His magic flared again, itching to be let loose and Magnus moved, stalking towards the entrance he could see. Circle members rushed out of the door, their weapons drawn and Magnus didn’t stop his stride, flames engulfing them all with a wide sweep of his arms. They were dead within seconds. 

A quick pulse of his magic and the doors were gone, obliterated by the magic now crawling over his entire body. Magnus had only an instant to register Alexander, almost naked, strapped to an altar, both of his arms riddled with gashes, blood sluggishly creeping from the wounds, his body unnaturally pale before his magic  _ erupted _ in fury, destroying those standing around Alexander, those responsible. 

Both shadowhunters standing by the altar were gone, nothing more than smoke and ash, but the warlock leading the spell had had enough time to throw up a shield in his hesitation. Magnus was dimly aware that the warehouse around them had been almost entirely obliterated by the explosion of his magic. 

“Y-you’re too late,” she laughed. “You might have stopped me from raising Lilith, but you’re too late to save your precious shadowhunter.” 

Magnus’ magic flared again, darkening to almost black, the faintest hint of red remaining. He threw his magic into her and twisted, tangling his magic with hers, sinking claws into it. “We’ll see about that,” he whispered. With a vicious twist of his hands, he removed her magic, pulling it out of her piece by piece, releasing it once it was no longer tied to her. Another quick twitch of his fingers and she was unconscious, mundane and mortal. 

“Mag’us,” Alec managed to breathe out, forcing his eyes open. He blinked slowly. 

“Alexander,” Magnus breathed, rushing towards the altar. Now that he was closer, he could see just how much blood Alexander had lost and he grabbed for Alec’s hand, squeezing it tightly. “Alexander, focus on me, we’re going to get you help. Stay with me, okay? We’re getting you help.” 

“No time,” Alec mumbled, trying to squeeze Magnus’ hand, but his arms burned, they’d been hurting for so long, he almost couldn’t remember when they had hadn’t hurt. “We, I….m’sorry…” 

“Don’t try to talk,” Magnus soothed, taking a deep breath. Alexander didn’t need death and destruction, he needed healing and his power was resisting the shift he demanded of it. He pushed it into Alexander regardless, focusing on the wounds he could heal. But he’d lost too much blood. Far too much. 

“g’nus, s’ok…” Alec managed, sucking in a shallow breath, his eyes fluttering in pain. 

Magnus choked down a sob and held onto Alexander’s hand tighter, pushing the magic into him, but it wasn’t enough, he wasn’t made for this, he wasn’t enough to save Alec. Like this, he could feel Alexander’s pulse slowing, weak and thready. 

“Don’t leave me,” Magnus whispered, pressing a desperate kiss to Alexander’s hand. “You have to fight, Alexander, help is coming, I promise.” 

This time Alexander didn’t answer him and Magnus could feel him fading away. He ripped off one of his necklaces, the one with the thick leather cord he rarely removed and wrapped it around their clasped hands. 

“I am not letting you leave!” Magnus snarled, blinking hard against the tears in his eyes. He sucked in a hard breath and used his magic to slice his free hand across the palm, dipped it in Alexander’s blood on the altar then covered their clasped hands with his bleeding one. He closed his eyes and focused on the faint thrum of Alexander’s pulse. 

“With my blood and thine, I tie myself to thee,” Magnus chanted, slamming his eyes shut. “We are bound a-and,” he swallowed, forcing his eyes open, staring at Alexander’s face. “Forever bound shall we remain. None shall not sunder us, not age, not  _ death, _ by all the power I possess.” 

The air went still around them and Magnus uttered the final words of the spell. “This I vow, on the strength of my love for thee.” 

Magnus was vaguely aware of Catarina shouting his name when everything went blindingly white. Alec’s pulse kicked reassuringly against his hand, strong and steady. It was enough. Magnus let himself drift because he’d done it. He’d saved Alexander and that was what was… 

**Author's Note:**

> IMPORTANT NOTE: Yes, you will find out more about everything that happened at the end there in the next installment. And YES there is absolutely 100% a happy ending in store for our boys. 
> 
> Comments and Criticisms welcome!
> 
> You can find me here:  
[AriaLerendeair](https://arialerendeair.tumblr.com/)
> 
> And on twitter over here:  
[Aria_Lerendeair](https://twitter.com/Aria_Lerendeair)
> 
> Want to come hang out in a Shadowhunters Discord server?  
[Join Us Here!](https://discord.gg/A9CEA2G)


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